In a bowl, combine pancake mix, milk, oil and egg. I a 12 inch oven proof skillet, melt butter,stir in brown sugar,and apple slices: saute until sugar is dissolved. Pour pancake batter over apples, over medium heat until bubbles form on top of pancake. Bake uncovered at 350 degrees for 12-17 minutes or until golden brown. Invert on serving platter and serve with syrup.